New York City Comptroller John Liu’s spokesman has left his campaign team, which has been weighed down by an ongoing federal investigation of its fundraising operations.

The outgoing campaign spokesman, George Arzt, downplayed the significance of his departure in an interview Friday, saying his role had always been intended to be “month-to-month” when he joined Liu’s campaign in December.

“It lasted longer than I expected,” Arzt said. “You know I think the world of John, and it certainly was an exciting and challenging opportunity, but I think it’s time to move on.”

Liu, the city’s chief financial officer, spent more than $180,000 on legal fees in the most recently completed six-month reporting period, according to campaign finance filings. His former campaign treasurer and a campaign contributor have been charged with fraud; Liu hasn’t been accused of wrongdoing.

Arzt said he didn’t believe that the distraction of the fundraising investigation had derailed Liu’s campaign efforts.

“I think he’s done very well with handling the investigation,” Arzt said, “and even though it comes up every now and then, I believe he’s on track to run for mayor.”